A filtration system for cleaning high temperature raw gas containing fine particulates such as that discharged from coal gasification and fluidized bed combustion processes is described in U.S. Pat. No. 4,343,631 to Cliberti. Plants that discharge raw product gas at temperatures in the range of 1200.degree. F. to 1800.degree. F. result in subjecting filtration equipment to rapid failure. Commercial devices for hot gases such as cyclones, are useful for removing larger particulates but are of limited value in removing particulate smaller than 5 to 10 microns.
Porous filters of a cordierite material are known in the art. U.S. Pat. No. 4,257,810 to Narumiya relates to a porous body having a three dimensionally network cellular structure with a plurality of interconnected voids which is made by impregnating an an open cell, flexible polyurethane foam with a ceramic slurry. U.S. Pat. No. 4,396,565 to Tomita relates to filter for exhaust gases formed by immersing a urethane structure into a slurry and subsequently firing to form interconnected. U.S. Pat. No. 4,416,675 to Montierth relates to a honeycomb filter which can be formed by burning out a fugative additive to provide interconnected open porosity in the thin walls of the sintered material.
Cordierite ceramic heat recuperators employing a ceramic cross-flow configuration are known. U.S. Pat. No. 4,130,160 to Dziedzic et al relates to one such structure. U.S. Pat. No. 4,235,855 to Cleveland relates to a process for forming synthetic cordierite ceramic bodies.
The prior art does not concentrate on a method of making a cordierite ceramic filter element having a porous membrane for removing small particulates from a combusted hydrocarbonaceous material. Their is a need improved techniques for making a cordierite ceramic filter element of the above type.